The RHJ/Le rhino mutant: description of a unique murine model of autoimmunity.

The BALB/c HuDI-hrrh rhino mutant, which is no longer available, was an unusual murine model with prominent hepatic inflammation and fibrosis. The current report describes the early appearance of hepatic portal tract inflammation and antinuclear antibodies in the RHJ/Le mouse, a related rhino mutant which is distributed from a commercial source. All homozygous RHJ/Le rhino (hrrh hrrh) mice examined serially from 2 to 18 months of age developed inflammation of hepatic portal tracts. In 81 per cent of mice, portal and central veins were infiltrated with mononuclear cells. Focal infiltrates were found in salivary, Harderian and lacrimal glands and in the pancreas. Isolated animals had myositis involving skeletal muscle and myocardium. Heterogeneous antinuclear antibodies were detected in sera from 100 per cent of rhino mice and antibodies to DNA were present in 28 per cent of mice aged 6 months. Homozygous HRS/J hairless (hr/hr) and BALB/c controls failed to show consistent abnormalities in exocrine glands or liver. We conclude that the RHJ/Le rhino mutant spontaneously develops antinuclear antibodies and mononuclear cell infiltration in liver and exocrine glands. These animals provide unique opportunities to examine inflammatory lesions localized to specific target organs in an animal model of autoimmunity.